SMEDG – PREVIOUS MEETING

DATE: Thursday 11th February 1993 at 5.15pm

VENUE: Rugby Club – 1st Floor

SPEAKERS: Bob Valliant – General Manager, Tri Origin Exploration Ltd

TOPIC: “Hemlo-style gold mineralization in the Canadian Shield” Gold deposits such as at Hemlo, Ontario and Bousquet, Quebec now account for a significant proportion of Canadian Shield gold production. These deposits are stratiform and characterised by a variable pyrite content, associated metals including Cu, Zn, Ba, Mo, Sb, Hg, As and Mn and stratabound sericite and aluminous alteration assemblages. This style of mineralization occurs near the stratigraphic top of fine-grained, quartz crystal-rich felsic volcanic rocks which are distal from major volcanic centres and adjacent to thick accumulations of sedimentary rock. The lithofacies boundaries are generally associated with major structural breaks which do not appear to play a deposit-scale role in formation or localization of ore. This characteristic geological environment remains relatively unexplored for stratiform, pyritic gold deposits which remain attractive targets even during periods of low gold price.

The Hemlo Gold Deposit, Northern Ontario, Canada. Venetia Bodycomb